The following disclosure relates to electrical circuits and signal processing.
An electrical circuit can be designed using two or more integrated-circuit (IC) technologies. For example, emitter-coupled logic (ECL) devices can be used in portions of a circuit that require high-speed operation, and complimentary metal-oxide semiconductor (CMOS) devices can be used in other portions of the circuit to save space and power. When multiple IC technologies are used in a circuit, a signal conversion circuit typically is used to interface between the different technologies.
A signal conversion circuit is used, for example, because an ECL circuit can receive a 5-volt supply voltage and produce a differential signal with a 700-millivolt swing. A CMOS circuit can receive a 3.3-volt supply voltage and produce a single-ended signal with a 1500-millivolt swing. A signal conversion circuit to convert a signal from ECL to CMOS typically converts the differential ECL signal to a single-ended signal and amplifies and shifts the level of the signal, producing a signal with voltages suitable for use in a CMOS circuit.